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1.
褪黑素调控根系生长和根际互作的机制研究进展 总被引：1，自引：0，他引：1
2.
基于生长函数的大豆根系生长的三维可视化模拟 总被引：11，自引：3，他引：11
植物的可视化模拟与仿真能为植物生长研究提供直观、迅捷的科学研究方法.植物根系在生长介质中的三维空间造型与分布,对水分养分的利用具有十分重要的作用.为了避免植物根系生长环境的不可见性和次要因素的影响,定量地直观地研究根构型的适应性变化,将植物根构型的多个生长函数和植物根系的形态发生模型耦合起来,结合可视化方法,建立了植物根系生长的三维可视化模拟系统.以大豆根系为研究对象,根构型的生长函数采用前期研究已获得的三次多项式形式;形态发生模型采用微分L系统理论编译其生成规则;可视化方法采用一系列连接在一起并平滑处理的圆台代表根轴.系统设计成只需输入三次多项式形式的生长函数的系数,就可直观地、连续地、可控地获得该根系生长的可视化图形和根构型几何参数. 相似文献
3.
植物根系构型即根系在其生长介质中的生长与分布,包括根系长度、根系分支和根系生物量等,能够将植物固定在土壤中并有效吸收水分和矿质养分,直接影响植物的生长和发育。根系构型受多种因素的影响,包括土壤水分、养分和根际微生物,传统方式主要依靠化学肥料增加土壤养分进而改善根系生长,但是化学肥料会对环境造成危害,根际微生物作为植物的“第二基因组”,能够改善初生根、侧根和根毛的发育,促进植物的生长和根际养分吸收,近年来基因组学−代谢组学、基因组学−转录组学等多组学关联技术的应用揭示了微生物的促生机制,为微生物菌剂的开发提供了新思路。基于该领域的研究现状,本文阐述了根际微生物（AMF、PGPR、根瘤菌）对根构型的调控机制包括激素调控、固氮、溶磷、释放挥发性有机化合物四个方面,并描述它们通过这四种机制增加植物根系长度、根系分支,促进根毛发育的调控效应,基于上述结论,植物根际微生物可以有效改善根系生长,但实际应用效果还有待研究,量化不同机制的相对贡献率以及提高微生物菌剂在实际应用中的稳定性是后续研究的重点。 相似文献
4.
在论述植物根系作为养分的主动吸收槽，对根示养分生物有铲性产生重要作用的前提下，本文扼要讨论了根际ＰＨ值变化，根分泌螯合物与 性物及根际微生物在根际土壤养分活化中的作用过程，并重点评述了有关养分活化与吸收模拟模型的进展与发展趋势。 相似文献
5.
不同土壤层次供应水分和养分对玉米幼苗生长和吸收养分的影响 总被引：12，自引：3，他引：12
本试验模拟滴灌方法 ,在不同土壤层次进行灌水和施用氮磷养分的盆栽玉米试验 ,旨在探讨在不同土壤层次供应水分和养分对夏玉米幼苗生长、根系空间构型及玉米对养分吸收的影响。试验表明 :在土壤深层进行滴灌可以有效降低土面蒸发 ,提高水分和养分的利用效率 ,从而显著提高玉米幼苗的生长量 ;在不同层次施肥灌水 ,对玉米根系在土壤中的空间构型影响很大 ,进行深层滴灌可以极大促进根系在较深土壤中的发育 ;在不同土层施肥灌水对玉米幼苗吸收N、P、K三种养分的能力也有影响 ,深层施肥灌水提高了玉米对 3种养分的吸收量 相似文献
6.
结构与功能反馈机制下根系生长向性模拟 总被引：1，自引：1，他引：0
借助于根系生长发育的功能-结构模型,模拟了根系生长的向地性、向水性与向肥性。研究中采用Voxel体元对根系生长的土壤区域进行离散化,并设定各Voxel元8个顶点的土壤含水量、养分浓度;采用根系功能-结构模型描述了不同生长周期下根系在三维土壤空间的生长;采用空间碰撞检测技术,确定各根元所占据的Voxel元,并以根元中点坐标与其所占据的Voxel元的各顶点距离倒数作为权重,计算根元生长区域的土壤平均含水量与养分浓度;利用三基点阻力法,计算得到土壤含水量、养分浓度对根元库强的校正系数,重新计算当前周期下根系可利用的生物量在组成根系的各根元中的分配,并调整根元的生长方向。最后,在设定的不同土壤含水量与土壤养分分布情景下,模拟了根系的空间生长与分布。模拟结果显示借助根系的功能-结构模型,在特定的情景下,能够模拟根系生长过程中的向地性、向水性与向肥性。根系在空间生长是一个复杂的过程,在特定的条件下,能够通过一定的农业措施,如灌溉、施肥,改变其空间生长与分布,使得作物高效地利用土壤水分、养分资源,从而实现可持续发展的生态农业 相似文献
7.
集约化互作体系植物根系高效获取土壤养分的策略与机制 总被引：6，自引：1，他引：5
8.
根际是养分进入作物系统的门户,也是土壤-根系-微生物相互作用的微域。根际界面过程决定了氮磷养分的供应强度和有效性,最终影响了氮磷养分的利用效率和作物生产力。近年来,国内外在揭示农田土壤-根系-微生物系统中不同界面的养分转化、吸收和运输机制方面取得了一些新进展。在不同时空尺度上分析了影响土壤氮磷转化微生物组成的影响因子;研究了丛枝菌根系统形成的信号机制及其对氮磷吸收的基因调控机制;从信号网络、根系质子分泌和根构型的角度系统揭示了作物根系应对根际环境氮磷养分供应的形态和生理响应机制。未来针对根际氮磷高效利用问题,需要深入研究土壤-根系-微生物不同界面的协同机制和调控原理,在根际微域和土壤团聚体尺度开展微生物食物网及其关键功能微生物分布格局和演替规律的研究;揭示根构型对根系–微生物协同结构和功能的影响,研究养分缺乏条件下根内质子分泌和关键转运蛋白对根系生长和养分吸收的调控机制;针对粮食作物,研究根系-微生物对话中已知信号物质(如独脚金内酯和N-酰基高丝氨酸内酯)和新的信号物质(小RNA)的网络作用机制及其对多养分协同代谢的影响;最后,针对不同气候、土壤、作物类型区,提出提高氮磷利用效率的根际生物调控途径和措施。 相似文献
9.
水稻根系氮磷钾吸收特性及其模拟模型研究 总被引：3，自引：0，他引：3
为定量研究水稻一个生长周期的氮磷钾吸收特性,开展水培和土培盆栽试验。结果表明,7个水稻品种的30个模拟模型中,有29个模型达到统计显著水平,说明提出的模拟模型能很好地拟合水稻不同生育期的养分吸收动态。由模拟模型分析可得到水稻根系养分吸收常数、最大养分吸收速率和最大养分吸收量及其出现的时间等养分吸收特征参数。根系养分吸收常数平均值是K>N>P;不同品种间根系钾吸收常数有较大差异,氮和磷的差异则较小。养分最大吸收速率和最大吸收量及其出现时间的计算结果表明,水稻氮钾吸收过程基本同步,磷则稍晚。土培试验表明,平衡施肥明显提高水稻根系养分吸收常数、氮磷钾的最大吸收速率和最大吸收量,显著提高根系对氮磷钾的吸收能力。 相似文献
10.
均质壤土下玉米根系三维空间分布的模拟与参数分析 总被引：3，自引：0，他引：3
根系三维结构的确定对研究原位状态下根系吸收水分、养分有重要的意义[1,2]。国内外很多研究者已经将定量化模拟与分析根系三维结构作为培育资源高效利用的作物新品种、提高SPAC系统中物质、能量运移与分布模拟精度的重要突破手段与方法[2~5]。目前,关于根系结构研究多采用三种方式。第一种方式,假设根系在水平方向均匀生长与分布,在根系生长的垂直一维方向上把土壤空间划分为若干层,来研究根系结构与生长的空间分布[6]。第二种方式采用三维根系生长模型,在试验测定或者人工设定模型参数的条件下,实现以根段个体为研究对象的根系生长的三… 相似文献
11.
Bernd Steingrobe 《植物养料与土壤学杂志》2005,168(4):496-502
Plant fine roots are subject to continual turnover, i.e., old roots die during the plant life cycle and are quickly replaced by new roots. New roots grow partly into undepleted soil areas and can take up nutrients at a higher rate than old roots. This is one possible advantage of root turnover. It has been shown that root turnover of several plant species increases when P and/or K supply is limited, indicating an efficiency mechanism. The objective of this study was to assess the maximum benefit for nutrient uptake by root turnover and to determine which soil or plant properties influence this process. Based on a data set of field‐grown faba beans, a sensitivity analysis with a transport and uptake model was performed, i.e., several input parameters were systematically varied to assess their importance for nutrient uptake of a root system with and without fine‐root turnover. The calculations were based on the assumptions that all new roots grow into undepleted soil areas and that no inter‐root competition occurs. Model calculations indicated that a root system with a high but realistic turnover rate can take up twice the amount of P or K compared to a stable root system without any turnover. This benefit on uptake is higher at low concentrations of these nutrients in soil solution, low soil water content, or high maximum inflow. However, measured uptake under poor conditions of nutrient supply is often higher than calculated uptake, even when root turnover is taken into account. This indicates that root turnover might be an efficiency mechanism, but not the only one. 相似文献
12.
作物根系吸水特性研究进展 总被引：9，自引：0，他引：9
综述了作物根系吸水模型的研究现状、存在问题和研究展望。根据根系吸水源汇项S(z，t)的构造方法不同，可将作物根系吸水模型大致分为微观模型和宏观模型。微观根系吸水模型能够描述根区微域内土壤水分运动规律，但根系分布的均一性假设和田间情况相差较大；宏观根系吸水模型的边界条件容易确定和控制，但该类模型忽略了根系微域的水势梯度和其他类似现象。今后的研究应集中在对以往根系吸水模型进行修改与完善、根系过程(吸水、吸肥、渗流、呼吸等)模拟以及根系结构与分布等方面。 相似文献
13.
沙培条件下磷、 钾、 钙亏缺对枳（Poncirus trifoliata）幼苗根系形态及营养吸收的影响 总被引：6，自引：2，他引：4
【目的】根系是吸收水分和养分的主要器官,对于多年生木本果树的生长发育尤为重要。由于果树根系庞大、 分布错综复杂,对根系构型和空间分布等的研究相对较少。本文利用计算机扫描系统及其图像分析软件观测根系二维形态参数,并用原子吸收法测定植株养分含量,以探索养分亏缺对枳根系形态的影响,以及根系形态变化与植株养分吸收的关系。【方法】本试验在沙培条件下,以柑橘砧木枳(Poncirus trifoliata)实生苗为试材,研究了缺磷、 钾和钙对其根系形态以及植株体内营养元素含量的影响。利用爱普生数码扫描仪（Expression 10000XL 1.0, Epson Inc. Japan）扫描根系,并用WinRhizo Pro (S) v. 2004b软件(Regent Instruments Inc., Canada)分析获取根系总长、 总体积和总表面积等二维形态参数。利用原子吸收光谱仪(SPECTR AA220)测定样品K、 Ca、 Mg、 Fe、 Cu、 Zn等元素含量。【结果】从扫描数据可知,3 种缺素处理对枳幼苗根系形态结构有较大的影响,即在缺素时根系总长、 表面积和体积均显著降低,缺P处理使枳实生苗粗根的根系长度、 表面积、 体积显著降低,但是增加了中等粗根的表面积和体积; 缺K和缺Ca处理的中等粗根根系长度、 表面积和体积均显著低于对照; 3种缺素处理均显著降低了细根和粗根的根系长度、 表面积和体积。不同缺素处理对植株根系和地上部生长的影响也存在差异,缺P对地上部的抑制作用显著强于根系,缺K处理对根系生长的抑制作用较强,缺Ca对根系和地上部生长的抑制作用均较小。缺Ca处理植株体内Zn和Fe浓度均显著增加但Ca浓度降低,缺P时植株体内Ca和地上部Zn浓度增加,而缺K时植株体内Ca、 Zn浓度增加但Fe和K浓度均显著降低。【结论】不同缺素条件下枳实生苗根系形态各异,导致根系对不同养分的吸收能力不同,从而使植株体内K、 Ca、 Zn、 Fe等养分含量发生改变,最终影响整个植株根系和地上部的生长,表现出各缺素环境所特有的树体特征。 相似文献
14.
This report summarizes research aimed at describing the processes and quantifying the factors affecting transfer of P and K from soil into plants. Soil properties related to availability and plant properties reflecting nutrient acquisition were determined. Their interactions in the rhizosphere and their importance for nutrient supply of plants were studied by a combination of measurements and calculations using a simulation model. Phosphorus and potassium uptake by roots decreased P and K concentration at the root surface and caused characteristic depletion profiles in the adjacent soil. The shape of the profiles depended on the effective diffusion coefficient, the concentration of the nutrient in soil, morphological properties of the roots and on influx into roots. The degree of depletion at the root surface indicated the proportion of the nutrient potentially available in the soil. The shape of the depletion profiles reflected the amount of the nutrient taken up by a root section. The parameters found to describe nutrient acquisition are (i) influx per unit root length, (ii) root length per unit shoot weight (root/shoot ratio), and (iii) the period of time a root section absorbs nutrients. Plant species differed considerably in these properties. In order to integrate the processes involved and to evaluate the importance of individual factors, the Claassen-Barber model was used. Depletion profiles and nutrient uptake calculated with this model were in good agreement with measured values in a number of cases. However, at low P supply, plants absorbed substantially more P than the model predicted. This indicates that influx in this case is supported by mechanisms not properly taken into account yet. Influx per unit root length depends on morphological properties of and nutrient mobilization by roots. Root hairs increase root surface area per unit root length. In addition, because of their small diameter and geometric arrangement in soil, root hairs are specially apt to gain from diffusion when concentration gradients are small. This applies even more to VA-mycorrhizae. Their hyphae are longer and thinner than root hairs and can thus deplete larger volumes of soil per unit root length. Root-induced changes of soil pH increased the size of P depletion profiles, indicating that roots can mobilize soil P by this mechanism. Both acid and alkaline phosphatase enzyme activities were found to be markedly increased at the soil-root interface suggesting that soil organic P may contribute to the P supply of plants. 相似文献
15.
Some mechanistic models have been proposed to predict the No3^- concentrations in the soil solution at root surface and the NO3-N uptake by plants,but all these relatively effective non-steady state models have not yet been verified by and soil culture experiment.In the present study,a mathematical model based on the nutrient transport to the roots,root length and root uptake kinetics as well as taking account of the inter-root competition was used for calculation,and soil culture experiments with rice,wheat and rape plants grown on alkali,neutral and acid soils in rhizoboxes with nylon screen as a isolator were carried out to evaluate the prediction ability of the model through comparing the measured NO3-concentrations at root surface and N uptake with the calculated values.Whether the inter-root competition for nutrients was accounted for in the model was of less importance to the calculated N uptake but could induce significant changes in the relative concentrations of NO3^- at root surface.For the three soils and crops,the measured NO3-N uptake agreed well with the calculated one,and the calculated relative concentrations at root surface were approximate to the measured values.But an appropriate rectification for some conditions is necessary when the plant uptake parameter obtained in solution culture experiment is applied to soil culture.In contrast with the present non-steady state model,the predicted relative concentrations,which show an accumulation,by the Phillips‘ steady-state model were distinct from the measured values which show a depletion,indicating that the present model has a better prediction ability than the steady-state model. 相似文献
16.
P. R. Ernani J. C. P. Santos J. Kaminski D. S. Rheinheimer 《Journal of plant nutrition》2013,36(6):1067-1078
Mechanistic models need to be validated before being widely used. The Barber‐Cushman mechanistic nutrient uptake model has successfully predicted phosphorus (P) uptake in high‐P soils, but it has not been tested in soils with low available P. Some assumptions of this model (no influence of mycor‐rhizae and root hairs on nutrient uptake) may have different implications according to the soil P level. The objective of this study was to test the ability of the Barber‐Cushman model to predict P uptake for corn in an Oxisol with low P values as influenced by mycorrhizae inoculation. The experiment was carried out in a greenhouse, in a factorial with two levels of P (25 and 100 mg/kg), of limestone (pH 4.7 and 5.5), and of mycorrhizae inoculation (with and without). Observed P uptake was determined in the roots and in the shoots of 46‐day‐old corn plants. The predicted P uptake by the model was calculated using a computer program. There was a good agreement between observed and predicted P uptake (r2 = 0.97). The model, however, underpredicted the amount of P taken up by corn plants, probably due to the contribution of root hairs. Inoculation with mycorrhizae did not affect corn yield and had a small influence on both observed and predicted P uptake. The model predicted, respectively, 31% and 41% of the P taken up by plants for treatments with and without mycorrhizae inoculation. Sensitivity analysis demonstrated that P in the soil solution and the rate of root growth were the parameters that most influenced predicted P uptake, and that plant uptake kinetics had a small contribution. 相似文献
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18.
Amanda Black Ronald George McLaren Thomas Wilson Speir Lynne Clucas Leo Murtagh Condron 《Biology and Fertility of Soils》2014,50(4):685-694
The aim of this research was to identify and quantify gaps in currents methods and models for predicting the plant availability of selected nutrient and contaminant metals (Cu, Ni, Zn, Cd) in soil. This study investigated relationships between the relative solubility of Cu, Ni, Zn, and Cd determined by six extraction methods with short-term uptake by shoots and roots of wheat (Triticum aestivum). For Cu, Ni, and Cd, relationships between solubility and plant uptake were found to be different for shoots and roots, with Cu and Ni solubility being more closely correlated with root uptake compared with shoot uptake. Correlation coefficients for Cd concentrations in shoot and root tissue for all six solubility methods were poor (r 2?<?0.5), while corresponding results for Zn explained more than 50 % of shoot variation but less than 50 % of root variation. Soil Cu solubility explained up to 85 % of variation in root uptake compared with 42–55 % for shoot uptake. These results clearly demonstrated that purely chemical and passive diffusion mechanisms were inadequate predictors of Cd uptake by shoots and roots, together with Cu uptake by shoots. Thus further attempts at refining soil metal bioavailability assays based solely on chemical extraction without consideration of plant responses are unlikely to improve prediction of plant uptake. 相似文献
19.
H. Grimme 《植物养料与土壤学杂志》1983,146(5):666-676
It was the objective to study the effect of Al on Mg uptake by plants, precluding as far as possible the effect of Al on root growth. Oat plants were grown in a complete standard nutrient solution without any differential treatment, in order to obtain a set of plants which did not differ in the size, the morphology and the physiology of the root system. After the first harvest at the beginning of the stem elongation stage 4 different treatments were introduced: pH 5.5-6.0, pH 5.5-6.0 without Mg, pH 3.8-4.1, pH 3.8-4.1 + 0.3 mmole Al/l. Apart from these variations the composition of the nutrient solution remained unaltered. After another 10 days 2 vessels of each treatment were harvested. The final harvest was 14 days after the beginning of the differential treatments. The growth (in terms of dry matter yield) of neither the shoots nor the roots was adversely affected by the differential treatments, although the plants in the Al and Mg0 treatments showed distinct symptoms of nutritional disorder. The plants in the low and the high pH treatments differed neither in Mg uptakte nor in Mg concentration in the plants. However, the addition of Al to the nutrient solution reduced Mg uptake in the shoots to about 30% of that in the Al0 treatments, while there was a net loss of Mg in the roots in spite of the fact that dry matter increased. This means that net uptake of Mg was less than was translocated to the shoot during the period of differential treatments. With no Al in the nutrient solution the Mg concentration in the shoots declined by 3–8% between the first and the final harvest, whereas it increased by 22–35% in the roots. If, however, Al was added to the nutrient solution the Mg concentration dropped by 46% in the shoots and 70% in the roots. With the exception of Ca in the roots, the differential treatments had no effect on the uptake and concentration of Ca, K and P in the plants. In terms of dry matter the differential treatments did not influence root growth and it was concluded that Al had a direct effect on Mg uptake by either inactivating or competing for uptake sites or carriers. 相似文献
20.
Although per growing season nutrient uptake of adequately growing forest trees is less than the nutrient uptake of annual crop species, nutrient uptake per unit root length in trees is considerable. Because of high heterogeneity of soil conditions and root growth in forest soils, modelling of uptake processes is even more difficult for forest than for crop stands. Detailed studies show that white lips of growing tree roots have a high nutrient uptake capacity. However, most root tips are usually colonised by mycorrhizal fungi. These fungi can participate substantially in tree nutrient uptake, in particular in the utilisation of organically-bound phosphorus and nitrogen in soils. Mycorrhizal hyphae, root tips, and older root zones can all absorb water, but their actual contribution is difficult to assess. In this review, experimental results from our laboratory and literature data are used to describe the potential activity of tree roots and mycorrhizas in nutrient and water uptake. Methodology for in situ measurements must be developed to quantify at different forest sites the actual contribution of mycorrhizas and different root parts. 相似文献